Conventionally, in a process of manufacturing a semiconductor integrated circuit or a liquid crystal display, an object such as a wafer and a glass substrate is subjected to treatment such as exposure and grinding by various devices such as an exposure device and a grinding device. At this time, the object is attached to an attachment member.
As this attachment member, for example, JP 2012-518900 W describes a substrate supporting structure (attachment member) for clamping a substrate (object) by capillary force generated by liquid such as water, the substrate supporting structure including a surface (attachment surface) provided with a plurality of substrate supporting elements (protruding parts) for holding the substrate (object).
In such an attachment member, when hydrophilicity of the attachment surface is low, bubbles are generated in the liquid, so that attachment force for the object is easily lowered. On the other hand, when abrasion resistance of the protruding parts is low, particles are generated from the protruding parts by contact with the object, so that the object is easily contaminated.